1. Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings."
Doppler's Effect
Newton's law of cooling
Kirchhoff's Law
Stefan's Law
Answer: Option B
Explanation:
Doppler's Effect - The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.
Kirchhoff's Law - Kirchhoff's Law signifies that good absorbers are good emitters.
Stefan's Law - The radiant energy emitted by a black body per unit area per unit time is directly proportional to the fourth power of its absolute temperature.
2. Which instrument is used to measure strength of direct current ?
Stroboscope
Streoscope
Tangent Galvanometer
Tachometer
Answer: Option C
Explanation:
Stroboscope - is used to view rapidly moving objects,
Streoscope - is used to view two dimensional pictures,
Tachometer - is used to determine rotational speed of a shaft (used in aeroplanes and motor boats).
3. If no external force acts on a system of bodies, the total linear momentum of the system of bodies remains constant. Which law states this ?
Newton first law
Newton second law
Newton third law
Principle of conservation of linear momentum
Answer: Option D
4. What is the range of mercury thermometer ?
0 degree Celsius to 350 degree Celsius
-10 degree Celsius to 350 degree Celsius
-20 degree Celsius to 350 degree Celsius
-30 degree Celsius to 350 degree Celsius
Answer: Option D
5. What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it ?